Human T-cell receptors have been defined on inducer, suppressor, and class I and class II specific cytotoxic T lymphocytes as 90 kilodalton T3-associated clonotypic molecules. These are comprised of one 49 to 51-kilodalton alpha and one 43 kilodalton beta subunit, both disulfide linked. Peptide map analysis studies suggested that each subunit is comprised of constant and variable domains. Moreover, the precise molecular basis for this variability in the beta subunit has now been defined by DNA cloning studies, showing that similar to immunoglobulin heavy chain, specific V, D, J, and C segments fuse to form an active Ti gene. This process occurs in the thymus at an early stage of intrathymic ontogeny (stage II). However, surface expression of the T3-Ti complex is restricted to a minor population of thymic lymphocytes (stage III). The ability to identify variable region genes encoding the Ti beta subunit of the T-cell receptor (and shortly the Ti alpha subunit) makes possible, for the first time, analysis of human T-cell malignancies at the clonal level. Thus, it is now feasible to question the extent of clonal variability of tumors within and among clinical types by examining the V genes which are rearranged to form one of their active Ti subunits. This can be related to V gene utilization by "physiologic" T-cell and thymocyte populations. Our research will include: (1) cloning and sequencing Ti beta V genes from a variety of T-cell malignancies and performing frequency analysis of utilization of these V genes within human thymus and peripheral T-cell compartments; (2) examining the relationship of V genes employed by T-cell acute lymphoblastic leukemias, lymphoblastic lymphomas, and Sezary syndrome to determine whether there is restriction to a single clinical type of malignancy; (3) producing monocloncal antibodies against synthetic peptides corresponding to V gene sequences utilized by several of these tumor populations for direct tissue distribution analysis; and (4) determining whether restriction analysis of DNA from T-cell malignancies with Ti beta probes will be of diagnostic utility. An analogous set of experiments will be performed with the Ti alpha probe as soon as it is available. (AG)